Work

Investigating frost response, rootstock-dependent cold tolerance, and floral bud mortality in apple cultivars through transcriptomic insights

Year: 2025

Type: article

Abstract: Late spring frosts threaten the productivity of deciduous fruit trees. In this study, we investigated frost tolerance in two apple (Malus domestica Borkh.) cultivars, ‘Fuji’ and ‘Gala’, grafted onto ten different rootstocks, over the springs of 2021–2023, to elucidate cold-responsive genes and regulatory mechanisms. Trees on the ‘B.9’ rootstock exhibited superior frost tolerance, with lower floral bud mortality compared to the susceptible ‘M.26’. Using RNA-sequencing, we analyzed leaf samples from suckers of ‘B.9’ and ‘M.26’, and floral bud and leaf tissues from ‘Gala’ trees grafted onto these rootstocks. Samples were collected 12 hours before and 6 hours after a natural frost event in April 2021. Transcriptome analysis revealed extensive transcriptional changes, with 4,549 genes upregulated and 5,469 downregulated. Weighted gene co-expression network analysis (WGCNA) identified three significant modules based on module eigengenes (ME 6, ME 7, and ME 9) associated with the frost response. The ME 6 and ME 7 modules comprised 1,210 and 1,011 genes, respectively, while the ME 9 module included 163 genes, of which 6 were differentially expressed post-frost. Applying a 90% module eigengene connectivity threshold, we identified key hub genes, including MdAFP (ABI five binding protein 3), MdCBF4 (C-repeat-binding factor 4), MdEXP8 (Expansin A8), MdHSFC1 (Heat shock transcription factor C1), MdHXXXD (HXXXD/BAHD-type acyl-transferase family protein), MdLRR-RK (Leucine-rich repeat receptor-like protein kinase), MdRPK2 (Receptor-like protein kinase 2), and MdWBC11 (White-Brown Complex homolog/ABC transporter protein). These findings elucidate the genetic basis of frost resilience in apple rootstocks and pinpoint potential targets for genetic enhancement of frost tolerance.

Source: Plant Stress

DOI: 10.1016/j.stress.2025.100829

Authors: Amolpreet Kaur Saini, Khalil R. Jahed, Deisiany F. Neres, Robert C. Wright, Sherif M. Sherif

Institution: Virginia Tech

Language: English

Topic: Plant Physiology and Cultivation Studies

Subfield: Plant Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDG: Zero hunger

Open Access status: gold

Estimated APC paid: $2,310